Bruce is, it's true, a bit of a stickler about patrol schedules. Patrolling the city is one of - if not the - main duty that comes with being a member of the Bat Family, at least in terms of 'vigilante hours spent', and yes, it might be less-glorious than supervillain battles or the like, but cleaning up the day-to-day crime is just as important, and, honestly? He'd take a boring, run-of-the-mill patrol over a confrontation with one of the major villains any night. A night when nobody is getting up to anything big? That's a good night.
So he isn't particularly inclined to skip patrols. Or call them off early. Even if it's a boring night. Even if 'nothing's really happening'. Even if his patrol companion for the night is feeling like maybe it's worth calling it early.
Even he has to admit, though. That suggestion seemed a bit premature at the first roll of thunder, perhaps. But when it was followed by the sky opening up and absolutely dumping a sudden torrential downpour? Maybe a point was had.
Not that he'll admit it easily. No, rain happens. Weather is weather, and this weather is... uncomfortable, but a minor inconvenience, really. At least, that's his stated stance on the manner. The Dark Knight does not cease patrol on account of a little rain.
Call him stubborn. It's probably true. But he's inclined to stay up perched on his rooftop, peering through the downpour and pretending he can spot... much of anything, through the curtains of rain. ...It'll stop eventually, right? These flash storms often are quick. A few minutes, not a problem. ...Of course, it's been fifteen. And when a flash of lightning and almost immediate loud crack of thunder makes his companion jump slightly, Bruce sighs. Alright. Maybe this won't just be a quick little flash storm.
"One last scan of the area," he insists, "and then we can stop in at a safehouse. Check in with Oracle for a minute while this blows over."